Inclosed-fuse element.



E. E. ROBERTS.

INCLOSED FUSE ELEMENT. APPLICATION FILED MAY a. 191m 1,213,777. 4 rammed Jan. 23, 1917.

INVENTOR.

ATTORNEY.

j UNITED srnrns PATENT OFFICE I EDWARD, n. nonnn'rs; onnnn'rronn, .oonn-nc'rrcnr, ASSIGNQR rc mini JOHNSePRATT iconrnny, or nan'rronn, connncrrcmi. A conroaarron or oonnnc'rrcn'r.

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To all whomzz't may concern:

Be-itknownthat I, .EDWARD E. Ronnn'rs, apcit-izen of the United States, residing at -Ha rtford,;in the county of Hartford and Stateof Connecticut, have invented a" new and-useful Improvement in Inclosed-Fuse Elements, of .which'the following is a spec1- ll/1S a commonexpedient'to make the fusib ble. 1elements of certain classes of incloscdsecured, usually bysolder, to the exterior 2'0 terminals or blades by which the fuse is con-. nected in the circuit with which it is to be used; In the manufacture of such fuses it is necessary to. make up the fusible element as an integral structure before it is placed its casing and .the granular condensing material filled inabout it. In order to conn'ect the 'interiorterminals and form a support therefor it has been customary to. join J them by a centrally arranged rod, and as this 0 rod must be small yetrigid and must have :high electrical resistance and considerable dielectric strength, a glass rod is usually employedfor this purpose. This rod, however, being centrally. located andsurrounded by the ribbons, when the fuse is in use with a current somewhat near its rated capacity, is subjected to considerable heat, andbeing'ofglass this heat causes it to expand quite a 3 little. The casings of these fuses are usually miter-med of fiber which when heated has a tendency to dry out and shrink, and the shrinkage of the casings and the expansion ofv the glass supporting rod being opposite.

in effect, sometimes subjects the parts to considerabl'e stress. In fact the expansion of the glass rod has frequently torn apart the fusible ribbons and has brokenthe soldered connections between the interior terminals and the fuse blades. When the structure is .-0.-2..made sufficiently strong to withstand'thede .sjtructive effect of such'expansion thejsmall glass rod is liable to be fractured.-

The object of the vpresent invention is to so construct the fusible element of an in- 155 closed electric fuse "that the interior termi Specification of Letters Eatent.

Patented Jan. 23, 1917.

' Application filed May 8,1916. Seria1No.86, ()26.

nals' will be rigidly enoughsupported to per- ,mit' quick handling in the process ofmanufacture, and yet suflici-ently elastic so that if the tube shrinks the glass is not fractured, or if the glass expands and increases in length the ribbons are not disrupted and the soldered connections between the elementterminals and the fuse blades not'broken.

In attaining this object the interior conducting terminals to which the fusible rib bons are secured and which are soldered to the fuse blades, are yieldingly connected by a non-conducting rod, preferably by cementing one end Ofa glass rod in. a socket in one terminal and loosely serting the other end of the glass rod in a socket in the other terminal against 'a spiral spring located in said socket. This spring tends to thrust the parts away from each other and keep the fusible ribbons tight, and yet" will contract so as to permit shrinkageof theeliminate all danger of rupturing the ribbons, breaking the terminal connections, .or fracturing the glass.

Figure l'of the accompanying drawings shows a side view of a fuse embodying this casing or expansion of the rod and thus invention, withone end of the casing cut I open to show the interior. Fig. 2 shows a side 'view of the fusible element.

Fig. 4. shows a longitudinal section of the other end of the element. Fig. 5 shows a transverse section of the element.

In the form of fuse illustrated the glass Fig. 3 shows a longitudinal section of one end of the element.

supportingrod 1 has one'end cemented in a socket in the terminal 2 and its other end extending loosely into a socket in the terminal 3. A spiral spring 4 is placed in the socket in the terminal 3 so as to thrust be tween the bottom wall thereof and theend of the glass supporting rod. The terminals of the form of fuse shown have radiating lugs 5 to which the ends of the thin zinc ribbons '6 are secured. There may be any number of these ribbons, depending upon the desired capacity of the 'element. The terminals also have projecting ends 7 which are soldered to the blades 8. -It is preferred to place small "felt washers 9 011 the rod close to the terminal 3 so as to prevent the entrance of any of the filling material into the spring socket.

This element is placed in a casing 10 which is commonly made of a section of fiber tube.

On the ends of the tubular casing are placed are secured. These caps are usually perforated for the escape of air and gas when the g 5 fuse blows, and inside of the caps are washers 12'ofloosely Woven fiber which prevent the filling material from siftin out through the vents in the, ca s, but permit the out fioW of air and gas. he granular non- 1O conducting and condensing medium 13 is,

of course, filled into the casing after the fusible element has been located therein, but before the cap atone end is applied.

With this construction the supporting rod I 15 may be made of glass which .is of high electrical resistance, has considerable dielectric strengthand is rigid and suliiciently strong to Withstand all ordinary strains,

bothele'ctricand mechanical to whichv it is v'20 subjected. i This glass rod, when arranged in the mannendescribed, supports the, terminals and yet it is free to expand and the casing is free to contract Without rupturing,

the delicate ribbons or causing the soldered joints between the terminals and theblades to break. i v I The invention claimed is:

1-. A fuse element comprising conducting terminal's, a non-conducting supporting rod extending from-one terminal to the other,

cushioning means between one end-of the the ferrules or caps 11 to which the blades I connecting said terminals.

rod and one terminal, and metallic ribbons 3. A fuse element comprising metallic'e'o.

terminals, a glasssupportingrod with its ends extending into sockets in said terminals, a spring arranged in the socket of one terminaland thrusting against the endofsaid rod, and metallic ribbons connecting said terminals. 1 l

4. A fuse element comprising metallic terminals, a glass rod with its ends extend: ing into sockets in said terminals, a spring arranged in the socket of one terminal and .50

thrusting vagainst one end of said rod, Washers on said rod and closing the socket in the terminal containing said spring, and -metall1c ribbons connect-mg sa1d-* terminals.

5. A. fuse element comprising conducting terminals, a non-conducting supporting rod extending from one terminal to the other,

and yieldingly connected therewith, and fusible conductors joining said terminals. EDWARD E. ROBERTS.-

copies of this patent may be obtained (or five cents each, by memes: the commissioner of Patents,

' v washingtomp. 0." 

